Er 19 Low

Biasi Er 19 Fault Code

Also written as ER19 — same fault.

The Biasi Er 19 fault code means: your boiler is having trouble measuring the temperature of the cold water coming in, which may affect how well it heats your hot water.. It appears on 14 Biasi models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Domestic hot water inlet probe failure (if present)
Typical repair cost £90-160 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Biasi models that show the Er 19 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Biasi Er 19 fault code information on this page is sourced and cross-checked against the official Biasi service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026